From the NBC television show, Grimm.
Nick is from a long line of superhuman hunters, known as Grimms. Much of folklore and fairy tales, such as the original Brothers Grimm stories, are based on accounts of supernatural creatures known as Wesen. Wesen are half-human/half-beast creatures with the ability to hide among normal humans. Grimms can see them, however, and spent millenia hunting Wesen to protect ordinary humans. However, Grimms have developed a reputation for killing Wesen on sight, causing many Wesen fear Nick when they realize what he is, which can be as much a hindrance in investigations as an advantage.
As a Grimm, Nick is gifted with the ability to see Wesen when other humans cannot. However, this is only possible when they experience emotional stress, otherwise they look like ordinary human beings. What's more, Wesen can recognize Nick for what he is when he sees their true forms. Nick possesses genetic knowledge of hand-to-hand and weapons combat, learning new weapons quickly and often pulling off complex martial arts moves on instinct. He is stronger than he appears but not by much and is apparently resistant against supernatural compulsions (although Nick was still susceptible to the enthralling of the muse-like Wesen, the Musai). Additionally, Nick can usually profile people with uncanny accuracy based on a short glance. All Grimms appear to be good sketch artists. However, Nick is new to his heritage and still has a lot to learn.